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First of all, the question is tricky. Putting all this together may lead someone to think of Unity as a Dock, which it is not. Actually, it is a User Interface (see this as reference to this affirmation and this for the definition of a Dock).

Not sure why you defend Unity as NOT being a very inflexible, irresponsible taskbar. Unity can be used along with AWN, Docky, etc. It can be removed completely, if needed from any Unity based distro, if needed (above url in Distrowatch):

"8 • Re: 7 rolling releases (by hobbitland on 2013-03-04 12:48:17 GMT from United Kingdom)
I've stayed with Ubuntu 12.04.2 LTS but with Gnome 3 fallback and will move to XFCE for Ubuntu 14.04 LTS. I don't like rolling release as I heavilly remaster Ubuntu 12.04.2 with unity removed and gnome 3 fallback included plus lots of other tweaks."

My up-to-date Mint-KDE & Netrunner can emulate all of the above, and more:
Unity, Docky, Awn, Windows7, IOS, Cairo, Gnome, Mate, Cinnamon, etc - but not E17, which is too confusingly complex for a novice to modify atm.

All the smaller taskbars (Docky, etc) can emulate the power-hungry bigger brothers by adding more apps; Compiz, etc. Not sure why you seem ignorant of this.

The so-mentioned deficits of Docky come from your unfair exploration of Docky, versus your biased explorations favoring Unity. Docky allows easy removal, adding, ordering, re-sizing of its icons better than almost any other taskbars, including Unity. If you need cubic or wallpapers of your desktops, just add the apps that allow this, such as Compiz or Cairo.